Justin Bieber struggles to name all the continents

Teen pop star Justin Bieber struggled to name all the continents when asked by a US chat show host. In an appearance on last night's Late Show with David Letterman, Bieber required clues to remember Europe was a continent - and even offered the North Pole as an answer. Justin, 17, was put to the test after he said his job had taken him to every continent. But he struggled to recall all the places he'd visited. The Canadian star said: "I love it. I have a blast. I get to travel the world. I think I've been to every continent." David then asked: "How many continents are there?" The U Smile singer replied: "Asia, North America, South America, erm, Africa, Antarctica and the North Pole. Er, Canada." David continued: "There are two more, come on. These are easy ones. You've been to both places." Justin, who is currently dating Selena Gomez, replied: "Oh, Australia. And the last one is..." David then said: "I'll give you a couple of countries in the last continent - France." Finally Justin added: "Europe!" David said: "I understand why you have to do other shows, but here you actually learn something."